what size trolling motor for this bad boy???

[shaggy dog]

U.S. customs and border patrol has two boats that look like that with cabins on them in Houma. They ride around lake decade area often. I talked to some of them and they told me that the one with 4 engines burns 120 gals of fuel an hour at full throttle and 80 gals. an hour at cruise. The boats cost over $400,000 each.